At http://phobos.cosmos.ru/index.php?id=618&L=2 it is said that "After 2.5 hours flight (1.7 revolutions) at this based orbit the main propulsion system will be switch on to transfer the spacecraft into the elliptical orbit (250 km x 4150...4170 km), period 2,2 hours. After 2.1 hours (1 revolutions) 2-nd engine burn will transfer the spacecraft into an interplanetary Earth-Mars trajectory." But on http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=49084 is said that "At launch, the spacecraft will be inserted into a 200-km circular orbit around Earth with an inclination of 51.8 degrees. After four hours of flight (2.8 revolutions) in this orbit, the propulsion system will be switched on to transfer the spacecraft into an elliptical orbit (230 x 11100 km, period 3.65 hours) from where it is transferred onto a trajectory to Mars."

Can someone explain which one is correct?

I think the one from the phobos.cosmos.ru page is right, at least according to the TLEs they're giving on another page on that site which they've been publicizing to get people to observe the burns.

There are 2 engine burns. It is launched into a near-circular orbit. The 1st burn (after 1.7 orbits) raises the apogee to 4150 km. The 2nd burn, which occurs near perigee just about 1 orbit later, is the escape burn.

The idea is that '3' requires some third stage in addition to basic Zenit-2SB type vehicle. In the case of Fobos-Grunt, there is no third stage per documentation, even if Fobos-Grunt ADU propulsion unit is a clone of Fregat.

So what is unique about this rocket that makes it a Zenit-2SB41?

That it has a different fairing (like Zenit-3F) and probably a special payload adaptor to fit the Fregat-like propulsion module.

Does the international cooperation involved - okay, it's mostly China, but you know what I mean - mean real/hi-res launch pics, or just the usual postage-stamps?

There's a lot of European involvement on instruments, so I wouldn't say it is "mostly China." Plus, the Planetary Society has an instrument onboard, so it's possible they have somebody at the launch site.

I was glad to present the Bulgarian instrument with a fellow scientist from IKSI-BAS on the National radio! Right now I'm also working in the academy, although in a different institute... The scientist I know personally was very excited to talk to me about our participation on Phobos-Grunt. She was working on some of the most ambitious projects like the SVET greenhouse aboard Mir and she's a brilliant scientist here... A little offtopic - she told me that she was running an experiment in parallel with the Mars 500 crew - again, about greenhouses and growing plants in space. Right now I know that she has published a peer-reviewed article, but I didn't have much free time to read it. I will read it as soon as possible..

About the Bulgarian instrument Phobos-Grunt that is named Lyulin-Phobos... It's a small instrument - the same size as a pen! Our instruments dedicated to radiation science are small and cheap and that's why they are preferred in the whole world. Similar instruments flew aboard Mir and aboard the ISS. A similar version also flew aboard Chandrayaan-1 to the Moon in 2008. So here, in Bulgaria, we have a very good science group who work in the field of radiation science. I hear also they will work with Russia on the Luna-Glob project.

The instrument will measure radiation from distance 1.0 to 1.5 AUs from the Sun - this covers the distance from Earth to Mars... and it will also measure radiation in Mars orbit and on Phobos

The instrument will improve the current models about risks during possible Manned Mars missions in the future

The instrument will work together with our instruments on the International Space Station so our scientists can compare results...

I hope you understood everything I posted, I'm not a native English speaker...